Durable optical element

Abstract

A durable optical film or element includes a polymerized structure having a microstructured surface and a plurality of surface modified colloidal nanoparticles of silica, zirconia, or mixtures thereof. Display devices including the durable microstructured film are also described.

1. An optical film comprising a polymerized resin and plurality of surface modified nanoparticles of silica, zirconia, or mixtures thereof, wherein the optical film comprises a microstructured surface having a plurality of alternating zones of prism elements having peaks that are spaced at different distances from a common reference plane. 
     
     
       2. The optical film of  claim 1  wherein the microstructured surface comprises alternating zones of shorter and taller prism elements and the zone of shorter prism elements is at least as wide as the zone of taller prism elements. 
     
     
       3. The optical film of  claim 2  wherein the zone of taller prism elements is between 1 and 4000 microns. 
     
     
       4. The optical film of  claim 2  wherein the zone of shorter prisms elements is between 200 and 4000 microns. 
     
     
       5. The optical film of  claim 1  wherein portions of prism elements comprise peaks disposed at varying heights above a common reference plane. 
     
     
       6. The optical film of  claim 5  wherein the microstructured surface comprises a zone of shorter prism elements separated by a zone including a single taller prism element. 
     
     
       7. The optical film of  claim 6  wherein the taller prism element limits the physical proximity of a second sheet of film to the microstructured surface. 
     
     
       8. The optical film of  claim 1  wherein the prism elements are approximately the same size arranged in a repeating stair step or ramp pattern. 
     
     
       9. The optical film of  claim 8  wherein repeating stair step or ramp pattern comprises a zone of higher prisms and the zone has a width of less than 300 microns. 
     
     
       10. The optical film of  claim 1  wherein the microstructured surface comprises alternating zones of shorter and taller prism elements and the zone of shorter prism elements comprises elements of varying height. 
     
     
       11. The optical film of  claim 1  wherein the surface modified nanoparticle have a particle size of greater than 1 nm and less than 100 nm. 
     
     
       12. The optical film of  claim 1  wherein the nanoparticles comprise silica nanoparticles. 
     
     
       13. The optical film of  claim 12  wherein the silica nanoparticles comprise a silane surface treatment. 
     
     
       14. The optical film of  claim 1  wherein the nanoparticles comprise zirconia. 
     
     
       15. The optical film of  claim 14  wherein the zirconia nanoparticles comprise a silane surface treatment. 
     
     
       16. The optical film of  claim 14  wherein the zirconia nanoparticles comprise a carboxylic acid surface treatment. 
     
     
       17. The optical film of  claim 1  wherein the nanoparticles comprise silica and zirconia. 
     
     
       18. The optical film of  claim 1  wherein the nanoparticles further comprise zirconia, titania, antimony oxides, alumina, tin oxides, mixed metal oxides thereof, or mixtures thereof. 
     
     
       19. The optical film of  claim 1  wherein the optical film is a brightness enhancing film. 
     
     
       20. The optical film of  claim 18  wherein the microstructured surface comprises light-diffusing elements. 
     
     
       21. An optical film comprising a polymerized resin and a plurality of surface modified colloidal zirconia nanoparticles wherein the zirconia nanoparticles comprise a surface treatment agent consisting of carboxylic acid. 
     
     
       22. The optical film of  claim 21  wherein the resin has a refractive index of at least 1.50. 
     
     
       23. The optical film of  claim 21  wherein the polymerized resin composition has a refractive index greater than 1.56. 
     
     
       24. The optical film of  claim 21  wherein the optical film is a brightness enhancing film. 
     
     
       25. The optical film of  claim 21  wherein the optical film comprises a microstructured surface that comprises light-diffusing elements. 
     
     
       26. The optical film of  claim 21  wherein at least one surface treatment agent is 2-[2-(2-methoxyethoxy)ethoxy]acetic acid.